Various retinal analogs will be synthesized, irradiated with monochromatic light, and the various double bond isomers will be separated by high-speed liquid chromatography. After structure determination, the respective pure retinals will be tested for rhodopsin formation with opsin. The synthetic retinals will be tailored so that collectively they will give a clearer definition of the steric and chiral criteria of the opsin binding site and cavity. The mild non-photochemical and non-thermal bleaching process of rhodopsins utilizing methylene chloride will be applied to a variety of visual pigments including bacteriorhodopsin. The yellow fluorescent pigment which accumulates in the human eye lens and which may have a direct bearing on senile cataract is also under study.